1. Technical Field
The present invention relates to a fluid feeding pump which feeds a fluid.
2. Related Art
A circulation pump which circulates a fluid through a channel is previously known. The circulation pump has a pump chamber with a variable volume. After the volume of the pump chamber is increased to suck a fluid into the pump chamber from the channel, the volume of the pump chamber is reduced to pressurize the fluid in the pump chamber. The fluid is thus fed into the channel from the pump chamber. Therefore, by increasing and decreasing the volume of the pump chamber, the fluid can be circulated through the channel.
In the case where air bubbles enter the pump chamber, when the volume of the pump chamber is reduced, the air bubbles are compressed and fluid is not pressurized. Therefore, the fluid cannot be fed. Thus, a technique of providing the circulation pump with a detection device for detecting air bubbles in the pump chamber and carrying out maintenance of the circulation pump to remove air bubbles from inside the pump chamber when the air bubbles are detected by the detection device, is proposed (JP-A-2010-242764).
However, the above technique has a problem that the circulation pump is increased in size because the detection device for detecting air bubbles needs to be provided separately in the circulation pump. The technique of feeding a fluid using the pump chamber is not limited to the circulation pump and is also used for a fluid ejection device which ejects a fluid after narrowing the fluid fed from a pump chamber, with an ejection nozzle. An increase in size of the device similarly takes place when the detection device is provided in the fluid ejection device.